Time: 2pm

Location: 2N36

Title: 4D Gauge Theories with Conformal Matter

Abstract: One of the hallmarks of 6D superconformal field theories (SCFTs) is that on a partial tensor branch, all known theories resemble quiver gauge theories with links comprised of 6D conformal matter, a generalization of weakly coupled hypermultiplets. In this paper we construct 4D quiverlike gauge theories in which the links are obtained from compactifications of 6D conformal matter on Riemann surfaces with flavor symmetry fluxes. This includes generalizations of super QCD with exceptional gauge groups and quarks replaced by 4D conformal matter. Just as in super QCD, we find evidence for a conformal window as well as confining gauge group factors depending on the total amount of matter. We also present F-theory realizations of these field theories via elliptically fibered Calabi-Yau fourfolds. Gauge groups (and flavor symmetries) come from 7-branes wrapped on surfaces, conformal matter localizes at the intersection of pairs of 7-branes, and Yukawas between 4D conformal matter localize at points coming from triple intersections of 7-branes. Quantum corrections can also modify the classical moduli space of the F-theory model, matching expectations from effective field theory.

# Events

Time: 2pm

Location: 2N36

Title: Stochastic Particle Production in the Early Universe

Abstract: I will show some intriguing hints of universality in the occupation number of spectator/daughter fields that experience repeated stochastic particle production during inflation and reheating. The calculations are aided by a remarkable mathematical mapping between stochastic particle particle production in cosmology and current conduciton in disordered wires. Time permitting, I will discuss potential implications of the results for density perturbations from the early universe.

Time: 2pm

Location: 2N36

Title: Gravitational radiation from classical QCD

Abstract: I begin this talk by discussing perturbative classical solutions of the Yang-Mills equations coupled to dynamical point particles carrying color charges. By applying a set of color-to-kinematics replacement rules first introduced by Bern, Carrasco and Johansson (BCJ) in the context of scattering amplitudes, these are shown to generate solutions of d-dimensional string gravity, which we also explicitly construct. Agreement between the gravity result and the gauge theory double copy implies a correspondence between non-Abelian particles and gravitating sources with dilaton and axion charges. When the color sources are spineless and highly relativistic, dilaton and axion exchange decouple, and the solutions we obtain match those of pure gravity. I comment on possible implications of our findings to the calculation of gravitational waveforms in astrophysical black hole collisions, directly from computationally simpler gluon radiation in Yang-Mills theory.

Time: 1pm

Location: 4N12

Title: Bulk Entanglement Gravity

Abstract: Nature is quantum, but we human beings tend to think in terms of classical variables. I consider the emergence of spacetime and gravitation from a truly quantum-first perspective, in which our best description of the world is as a state vector evolving in Hilbert space. Everything else, including space, fields, and particles, is emergent from the state vector. Imagining that Hilbert space can be written as a tensor product of many factors, we can define emergent distances and areas from the entanglement between those factors. I will outline a set of conditions necessary for this entanglement data to describe an emergent geometry, and a further set of conditions under which quantum dynamics naturally leads to Einstein's equation for gravity, at least in the weak-field limit. This approach suggests that we should not think about quantizing gravity, but rather about finding gravity within quantum mechanics.

Time: 1:30 pm

Location: 4N12

Title: TeV Scale Lepton Number Violation: Neutrinoless Double Beta Decay & the LHC

Abstract:Determining the origin of neutrino masses remains a compelling challenge at the interface of nuclear and high energy physics. The standard see-saw neutrino mass mechanism postulates the existence of new lepton number violating (LNV) interactions at very high energy scales. In this talk, I consider the possibility that LNV interactions responsible for neutrino mass may exist at the TeV scale. I discuss how the interplay of searches for neutrinoless double beta decay and LHC searches for LNV processes may probe this possibility. I also discuss several theoretical issues pertaining to these searches for TeV scale LNV.

Time: 2:00pm

Location: 2N36

Title: String Zero Modes, T-duality, Vertex States and Entanglement

Time: 1:30pm

Location: 4N12

Title: Cosmological Bounces and Wormholes from Vorticity

Time: 2pm

Location: 2N36

Title: What is the black hole information paradox?

Abstract: Much thought has been devoted to solving the black hole information problem.

I'll argue that almost none of it has been asking the right question, and

will explain how (what I believe is) the right question is inextricably

tied up with the implications of diffeomorphism symmetry for the nature

of states and observables in quantum gravity. Moreover, I'll argue that

the paradox isn't really about black holes.

Time: 2pm

Location: 2N36

Title: Discrete Superconformal Matter

Abstract:

We construct a novel type of (2,0) discrete charged superconformal matter coupled to 6d supergravity using F-theory. For this we consider smooth genus-one fibered and compact Calabi-Yau threefolds quotiented by a freely acting automorphism.

The resulting geometries exhibit orbifold singularities in the base with so called multiple fibers over them which is where the (2,0) discrete charged matter resides. We show this presence to be necessary for anomaly cancellation which we proof in generality.

Moreover we show, that the multiple fiber gauges the (2,0) subsector by a discrete gauge symmetry. The discrete gauging shows itself by the presence of additional discrete charged hypermultiplets at the tensor branch of the (2,0) theories.

Time: 1:30pm

Location: 4N12

Title: Unification from Scattering Amplitudes

Abstract: Scattering amplitudes are fundamental observables that encode the dynamics of interacting particles. In this talk, I describe how to systematically construct these objects without reference to a Lagrangian or an underlying spacetime. The physics of real-world particles like gravitons, gluons, and pions are thus derived from the properties of amplitudes rather than vice versa. Remarkably, the expressions gleaned from this line of attack are marvelously simple, revealing new structures long hidden in plain sight. As an example, I describe how gravitons are in a very precise way equivalent to products of gluons---a fact with far-reaching theoretical and phenomenological applications. Lastly, I show how gravity serves as the "mother of all theories" whose amplitudes secretly unify, among others, all gluon and pion amplitudes.

Time: 2pm

Location: 2N36

Title: Coarse-Graining Holographic Entanglement

Time: 2pm

Location: 2N36

Title: Some new mechanisms for baryogenesis

Abstract: There is more matter than antimatter in the universe, and the origin of this asymmetry is still a mystery. The asymmetry can be generated dynamically in the early universe in a process referred to as baryogenesis but the standard model is not able to produce the amount observed. This is one hint that there is physics beyond the standard model. In this talk, I will present two new baryogenesis mechanisms, one using scalar-tensor theories and the other using Lorentz violating theories. I will discuss their phenomenology, and observational consequences, and show that they are able to produce the amount of matter that we observe in the universe today.

Time: 2pm

Location: 2N36

Title: Bit threads in space and time

Abstract: Bit threads are a reformulation of the Ryu-Takayanagi holographic entanglement entropy formula that offer several conceptual advantages over the standard minimal-surface formulation. After briefly reviewing the basic bit thread story, I will explain how to extend them in three interesting directions. First, I will show how bit threads offer a novel proof of the "monogamy of mutual information" inequality for holographic entanglement entropies, and how the proof suggests a very specific entanglement structure for holographic states. Second, I will explain how to include higher-derivative corrections. Finally, I will explain how to make bit threads covariant, reproducing the Hubeny-Rangamani-Takayanagi formula.

Time: 2pm

Location: 4N12

Title: Geometric engineering on flops of length two

Abstract: Type IIA on the conifold is a prototype example for engineering QED with one charged hypermultiplet. In type IIB, a single D3-probe at the singularity sees an abelian quiver gauge theory. The geometry admits a flop of length one. In this talk, we study the next generation of geometric engineering on singular geometries, namely flops of length two such as Lauferâ€™s example, which we affectionately think of as the conifold 2.0. IIA on the latter geometry gives QED with higher charge states. In IIB, even a single D3-probe gives rise to a nonabelian quiver gauge theory. We study this class of geometries explicitly by leveraging their quiver description, showing how to parametrize the exceptional curve, how to see the flop transition, and how to find the noncompact divisors intersecting the curve.

Time: 2pm

Location: 2N36

Title: Naturally Stabilizing the Weak Scale without Partners

We generalize and adapt Veltman's condition to create a framework which naturally addresses the little hierarchy problem. The resulting class of models is economical and ensures a minimum amount of fine-tuning for the bare Standard Model Higgs mass. To demonstrate this framework, we provide a model with an extended Higgs sector and a top Yukawa coupling that is no longer unity. The latter alleviates the largest radiative corrections to the Higgs mass. The former features significant dimension-full couplings that generate, at best, logarithmic corrections to the Higgs masses. The dimensionless couplings are small and do not generate large quadratic divergences or produce Landau poles. We find the cutoff can be raised to 5-7 TeV without significant fine-tuning for a large region of parameter space. We briefly discuss some of the phenomenology of the model and emphasize the importance of future $\bar{t}t h$ measurements.

Time: 1:30pm

Location: 2C8

Title: New Physics from Standard Model Measurements

Abstract: We traditionally look for new physics at colliders by trying to separate signals from Standard Model (SM) backgrounds. This approach has led to striking constraints from the LHC, but no discovery of new physics beyond the SM. In this talk I will highlight the alternate approach of using precision measurements of SM processes to search for subtle effects of new physics that is otherwise hidden from traditional searches. I will highlight examples where precise measurements of top quark, lepton, and jet production can be used to look for new physics.

Time: 2pm

Location: 2N36

Title: Cosmology of a Fine-Tuned SUSY Higgs.

Abstract: I will discuss some work in progress that explores whether a mildly fine-tuned Higgs boson, as in (mini-)split supersymmetry, can have interesting or observable cosmological consequences. As moduli fields oscillate, the Higgs can respond and perhaps acquire very large values along a D-flat direction. Possible consequences involve a burst of gravitational wave production and an altered estimate of the number of e-folds of inflation.

Time: 2pm

Location: 2N36

Title: BMS invariant fluids

Abstract: The Bondi-van der Burg-Metzner-Sachs (BMS) group is the asymptotic symmetry group of asymptotically flat spacetime. It is related to flat gravity in the same way that the conformal group is related to anti de Sitter gravity. However, while the conformal group is well known throughout field theory, the BMS group is rather mysterious. We show that the BMS group is closely related to infinite dimensional symmetry groups governing fluid dynamics. We use a relationship between gravitating systems and lower dimensional fluids on their boundaries to give a new derivation of the BMS group in three spacetime dimensions.

Time: 2pm

Location: 2N36

Title: Entanglement at a Scale and Recovery Maps

Abstract:

I discuss the amount of information in quantum field theory states reduced to a region, that cannot be recovered from its subregion density matrices. One can reconstruct the density matrix from its subregions using recovery maps. The vacuum of a conformal field theory is a quantum Markov state and the fixed point of both transformations. I define the entanglement of scaling as a measure of entanglement at a scale, and mention connections with C-theorems proofs in 2, 3 and 4 dimensions.

Time: 1:30pm

Location: 4N12

Title: Composite Higgses